First off, they should have secure and safe homes AWAY from people that will provoke them.
Secondly, I am a fan of dogs who have proven they will bite people WHEN they bite to enforce established boundaries they are often called PROTECTION dogs and are very valued for their traits by RESPONSIBLE dog owners that believe in secure fencing and the proper care of their animals.
First off, these dogs are running lose, not protecting anything. They attack whatever gets their attention. Second protection dogs are so much more than a dog who bites someone on his/her property. I have a dog now that will bite strangers in my hard without my permission, and he won't bite when he is outside the yard. This does not make him a protection dog. He is simply following instinct to protect his packs territory. Do I value this instinct? Yes, very much. But he is no trained protection dog. My parents had a police trained dog when I was a child. He had attack and release commands, among other differences. There is no comparison between dogs that are running the streets and attacking livestock, other dogs, and people to protection dogs. The dogs that I am having a problem with are mangy, sick looking, and very aggressive and the owner is an uncaring jerk who the sheriff gets many calls about. Unfortunately the sheriff writes the reports and it stalls and the DA office because they want the big cases like rape and homicide. So nothing gets done until someone gets seriously maimed or killed by these dogs and it is reported. I am not insane enough to risk a confrontation with these highly aggressive animals, not when there are 8 to 12 dogs in the pack with a litter on the way. I have fences and signs posted on my yard. Should the dogs still get in, I will do whatever is necessary to protect my family, my livestock, and myself.